In Equation 6, T is the time spent in the CP transmitting useful data, that is, the ratio of the length in bits of packet payload P (excluding the number of header and trailer bits, H) to the data rate R. The other time parameter, Ts, in (8) is the time spent sensing the channel during a successful frame transmission.
It has been proved, on the basis of simulation experiments and measurements carried out in networks, that thus defined calls can be described by the Poisson streams characteristics [2, 35, 36] in which variable bit rates of packet streams are replaced by constant bit rates called the equivalent bandwidth [37].
Therefore, energy efficiency η represents the ratio of the number of packet bits transmitted successfully to energy consumption.
Energy efficiency is a fair and appropriate metric to performance evaluation and comparison between the DT and CT, which can be defined as a ratio of the number of packet bits transmitted successfully to energy consumption.
With the length of the MAC frame body N MACFrameBody in bit, the number of packets for 1-periodic node with specific data arrival rate is text{num} = leftlceil {frac{{{lambda_{i}} times {t_{text{superframe}}}}}{{{N_{text{MACFrameBody}}}}}} rightrceil, (4).
Each packet is associated with a start tag and a finish tag, which correspond respectively to the virtual time at which the first bit of the packet and the last bit of the packet are served in fluid fair queuing.
A packet is considered in error if at least one bit of the packet is in error.
Average medium access delay, (mathcal {P}^{md}): It is defined as the average time taken for a secondary user to get access of the medium before transmitting a packet, that is the time before SU could transmit the first bit of a packet.
Here we define the energy efficiency as energy required to successfully transmit one bit of data packet.
